1. Technical Field
The present disclosure relates to a metal wiring, a method of forming the metal wiring, a display substrate having the metal wiring, and a method of manufacturing the display substrate. More particularly, the present disclosure relates to a metal wiring having reduced defects, a method of forming the metal wiring, a display substrate having the metal wiring, and a method of manufacturing the display substrate.
2. Discussion of the Related Art
A liquid crystal display (LCD) device is widely used in various fields such as an information display or a portable electronic device. The LCD device includes a thin film transistor (TFT) as a switching element that can control an intensity of a transmission light emitted from a pixel to display light and dark gradations.
As the LCD device having a large size and a high resolution is in demand, a metal wiring having a low resistance has been developed. For example, a process for forming a metal wiring using copper that has a very low resistivity has been developed. However, since the copper ion has a strong reactivity with silicon, the metal wiring having copper may be very easily silicidized. The metal wiring having copper has also very poor adhesion characteristics relative to adjacent layers. The above-mentioned problems cause difficulties in using copper wiring as the metal wiring of the LCD device.
To solve the above-mentioned problems, a metal wiring having a double-layered structure or a triple-layered structure that includes a different type of metal film on and/or beneath a copper film, has been developed to prevent diffusion of copper ions and to enhance an adhesion force relative to adjacent layers. However, the metal wiring having the different type of metal film and the copper film may not be uniformly etched due to etching rates that are different for the different metals.